Destroyed buildings are seen in the city of Sinjar. REUTERS/Raya Jalabi

Iraq must stabilise the northern region of Sinjar to help the Yazidi minority that was brutalised at the hands of the ISIL group return home, the International Crisis Group said on Tuesday.

A report by the conflict analysts said that Baghdad must set up a local administration and mediate between factions who hold sway over Sinjar to pave the way for the return of the Yazidis.

The majority Kurdish-speaking Yazidis follow their own non-Muslim faith, earning them the ire of ISIL. The militant group seized Sinjar city and surrounding villages in 2014 and unleashed a brutal campaign against the minority.

Thousands of men were slaughtered, women and girls abducted as sex slaves and boys sent to military training camps.

The UN has called the massacre of Yazidis a genocide.

Of the world's 1.5 million Yazidis, the largest community was in Iraq where it comprised about 550,000 people before being scattered by the ISIL attack.

About 100,000 have fled the country, while 360,000 have been displaced and now live in Iraqi Kurdistan or across the border in Syria.

ICG said Sinjar's occupation by "a succession of Iraqi and non-Iraqi sub-state actors has militarised the population, fragmented the elites and prevented the return of the displaced".

"Only the effective re-entry of the Iraqi state, mediating between factions and reinstating local governance, can fully stabilise Sinjar, lay the groundwork for reconstruction, allow the displaced to return and end foreign interference," it said.